Process of extracting zinc and copper from their ores.



UNITED STATES PATENT OFFICE.

CALEB' Gr. COLLINS, OF NEW YORK, N. Y., ASSIGNOR TO CALVIN AMORYSTEVENS, OF SAME PLACE.

PROCESS OF EXTRACTING ZINC AND COPPER FROM THEIR ORES.

SPECIFICATION forming part of Letters Patent No. 659,338, dated October9, 1900. Application filed O ob r 30, 1899. 3erial No. 735,289- (Nospecimens.)

To all whom it may concern.-

Be it known that I, CALEB G. COLLINS, a citizen of the United States,residing at New York, (Woodmere,) in the county of Queens and State ofNew York, have invented a certain new and useful Improvement in the Artof Extracting Copper and Zinc from their Ores, of which the following isaspecification sufficient to enable others skilled in the artto whichthe invention appertains to make and use the same.

My invention relates to the extraction of copper and zinc from theirores; and it consists, essentially, in subjecting the reduced or crushedores of these metals to the action of a solution of what is technicallyknown as niter-cake, a residuum resulting from the manufacture of nitricacid, thus utilizing for this purpose what has been practically a wasteby-product or one that is comparatively cheap, plentiful, and easilyobtainable.

In using the term niter-cake I refer to a residual substance composed,substantially, as follows: sulfate of sodium, 75.80 per cent. freesulfuric acid, 16.68 per cent.; water, six per cent.; insoluble matter,1.52 per cent.; total, one hundred percent.

The strength of the solution may be varied with relation to thecharacter of the ore to be treated. I have found a saturated solutiondesirable for general use. Should the ore carry iron, alumina, or othersoluble substance in large quantities, a weaker solution may be used toavoid waste by reason of the affinity of the solution for suchsubstances, its affinity for copper or zinc being greater, so that inthe absence of an excess of the niter-cake in the solution the latterwill take up only the copper or zinc. For instance, I have found whenusing a weak solution of, say, about 5 Baum scale that the solutionexercises a selective action on these metals.

The process consists in immersing the zinc or copper ore, roasted orotherwise, in a powdered state in a bath of water in which more or lessof the niter-cake is held in solution and in subjecting the powdered oreto the action of this solution until all the copperor zinc present isdissolved out and extractedfrom the ore. The bath is then filtered toremove the residual ore and the copper or zinc electrically depositedfrom the solution or otherwise precipitated, as may be preferred.

I am aware that it has been proposed to reduce gold ore by calcinationwith sodic sulfate or salt-cake, as in patent to C. P. Williams, No.292,605, of January 29, 1884; also, that it has been proposed to usenitercake and salt-cake for preparing gold ore for amalgamation anddesulfurization, as in patents to C. R. Squire, No. 309,168, of December9, 1884, and Nos. 312,586 and 312,587, of Feb ruary 17, 1885; but I amnot aware that powdered zinc or copper ores, either roasted or raw, haveever been treated to a solution of niter-cake for the purpose ofdissolving out the said metals, as above described.

What I claim as my invention, and desire to secure by Letters Patent,is-

1. The herein-described process of treating ores of copper and zinc, andother metals soluble only in a strong solution of the solvent, whichconsists in immersing the comminuted ore, in a solution containingsodium sulfate and bisulfate (inter-cake), in proportion to thecontained copper and zinc therein, but sufficient in strength todissolve only copper and zinc therefrom, and subsequently recoveringthese metals from the solution, substantially as described.

2. The herein-described process of treating ores of copper and zincwhich consists 'in immersing the comminuted ore in a solution containingsodium sulfate and bisulfate (niter-cake) removing the depleted ore andextracting the'metal therefrom by electrolytic action, adding morecomminuted ore to the remaining solution, and repeating the operation,substantially as described.

3. The herein-described process of treating ores of copper and'zinccontaining other metals soluble in any excess of solution which may beemployed above that required to dissolve the copper and zinc containedtherein, which consists in introducing comminuted ore into a solutioncontaining sodium sulfate and bisulfate (miter-cake) not exceeding 5 Banm, and subsequently reco veriug the copper and zinc from the solution,substantially as set forth.

CALEB G. COLLINS.

Witnesses:

D. W. GARDNER, GEO. WM. MIATT.

